Exports have fallen to their lowest level for six years, according to new research.
A survey of 1,250 firms found that just over half said overseas orders have remained constant in recent months, while 50% said sales have stayed the same.
Both measures have fallen to their lowest level since 2009, said the British Chambers of Commerce (BCC) and delivery firm DHL.
Scotland was the only part of the UK where firms reported an increase in overseas trade, while the biggest declines were in Wales, London and Northern Ireland.
John Longworth, director general of the BCC, said: "Driving export growth is key to reducing the UK's deficit and maintaining our global competitiveness.
"These figures make it clear that the UK's export drive is at risk of going into reverse gear, precisely at the time when it needs to be moving forward.
"Many firms are currently operating at capacity and are in need of support to invest in machinery or staff.
"Those businesses considering taking the leap and breaking into new markets desperately need access to the growth funding and working capital to enable this transformation.
"Success in export is all about having the right market information, and the right fundamentals - access to finance, a skilled workforce and good infrastructure connections."
Phil Couchman, chief executive of DHL Express UK, added: "We can mostly attribute the drop in export orders and sales to uncertainty in the eurozone, and the instability of the Chinese and wider global economy."